Evaluation of the Goal System Version 2.2 Solution Method for Interactive Constraint Scheduling Situations

THE GOAL SYSTEM version 2.2 is the latest in a lineage that includes Optimized Production Technology (OPT) and DISASTER. Earlier work with DISASTER revealed potential shortcomings with sequential schedule-building algorithms when multiple interactive constraints exist. Since THE GOAL SYSTEM version 2.2 has a capacity for simultaneous schedule-building, this study evaluated differences between the two algorithms. Using benchmark scheduling problems developed during the earlier evaluation of DISASTER, a set of THE GOAL SYSTEM solutions was created and compared quantitatively to both DISASTER solutions and solutions which optimally minimize maximum tardiness. A broad set of performance measurement criteria were also used to obtain a more comprehensive evaluation of the solutions. Performance of THE GOAL SYSTEM was quite good with respect to maximum tardiness. Performance with respect to average flowtime, percentage of tardy jobs, and total days late for a set of job orders was markedly poorer than the DISASTER solutions. The results were unexpected, since the simultaneous scheduling algorithm is less restricted in its options for schedule creation. The author concluded that the simultaneous feature of THE GOAL SYSTEM was better suited for conflict resolution during an iterative process than as a stand-alone scheduling algorithm.